Activation energy of bromate/bromide reaction in acidic solution

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Discussion Overview

The discussion focuses on the activation energy of the bromate/bromide reaction in an acidic solution, exploring the experimental setup, observations, and calculations related to the reaction kinetics. Participants share details about the reactants, products, and methods used in their experiments.

Discussion Character

  • Experimental/applied
  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant describes the reaction involving BrO3-, Br-, and H+ ions, leading to the production of Br2 and the formation of a gel-like substance at the end of the reaction.
  • Another participant proposes that the gel-like substance might be 2,4,6-TribromoPhenol and requests an experimental guide with concentration details.
  • A participant provides specific concentrations for the reactants used in a 3-minute reaction, including phenol, KBr, KBrO3, and H2SO4.
  • There is a question about determining activation enthalpy and the appropriateness of using false origins when plotting a graph of 1/T against the natural logarithm of the rate.

Areas of Agreement / Disagreement

Participants have not reached a consensus on the identity of the gel-like substance or the specifics of the experimental procedure. Multiple viewpoints regarding the activation energy calculations and graph plotting techniques are present.

Contextual Notes

Details regarding the concentrations and specific experimental conditions are provided, but there may be limitations in the information about the experimental guide and the assumptions underlying the activation energy calculations.

Who May Find This Useful

Students and researchers interested in reaction kinetics, particularly those studying bromate/bromide reactions and activation energy calculations in acidic solutions.

sspanzer
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1. given/known data
My work is about calculating activation energy of bromate/bromide reaction.
Besides KBr and KBrO3, phenol and methy red is also used. The Bromine produced react rapidly with phenol, once all the phenol is consumed, the bromine will decolorize the methyl orange indicator. In that way the time for a reaction to reach a certain point can be determined

Homework Equations


BrO3- (aq) + 5 Br- (aq) + 6 H+ (aq) → 3 Br2 (aq) + 3 H2O (l)

My question is, what is the gel-like substances i found at the end of the reaction?
 
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a guess

I would guess that it is 2,4,6TribromoPhenol : http://chemicalland21.com/specialtychem/perchem/2,4,6-TRIBROMOPHENOL.htm
But then I have a question for you : do you have an experiment guide for the experiment - I found the one from Bangor University, but there is no info about conentrations and so - I would be glad if you could send me a mail if you have it.
best wishes
finn
 
concentrations for a 3 min reaction are as follows:
0.01M phenol (0.94g in 1dm3) 70cm3
0.1M KBr (11.9g to 1 dm3) 35cm3
0.02M KBr03 (3.34g in 1 dm3) 35cm3
0.5M H2SO4 35cm3

hope this helps
 
did you manage to find the activation enthalpy? And when plotting a 1/T against natrual log of rate graph false origins are ok because I only need the gradient?
 

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